Electric oil heating apparatus



April 1945- J. D. MORGAN ETAL 2,373,084

ELECTRIC OIL HEATING APPARATUS Filed Nov. 25, 1942 2 Sheets-Sheet l INVENTORS JOHN D. MORGAN I; LEVITT BY a ATTORNEY 'vland flaw/Ir I urn HPPK/ 2 Sheets-Sheet 2 J. D. MORGAN ET AL ELECTRIC OIL HEATING APPARATUS Filed Nov. 25 1942 April 3, 1945.

INVEN TORS JOHN D. MORGAN P RCY. B. V 1' M w RNEY ATTO

Patented Apr. 3, 1945 UNlTED STATES PATENT OFFICE ELECTRIG OIL HEATING APPARATUS John D. Morgan, South Orange, and Percy B. Levitt, Millburn, 'N. J., assignors to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania Application November 25, 1942, Serial No. 466,862

'7 Claims.

This invention relates to improvements in electric oil heating apparatus and method of heating motor crank case oils in a purification operaticn.

In'the use of naval patrol vessels equipped with internal combustion motors, it has been common practice to change oil, and clean the motors after very short periods of use. This disadvantage has been overcome by purifying the crank case oil while the motors are in operation. conducted in a closed circuit from the motor, through purifying apparatus, into an oil storage tank, and back to the motor. Some naval patrol vessels of course are provided with two or .more motors, and the invention includes the separate or combined handling of the crank case oil from all of the internal combustion engines of a vessel. Furthermore, the invention contemplates the handling of the crank case oil from Diesel motors or gasoline motors.

in the purification of crank case oils in a cycle of the type referred to above, it has been found that purification can be made much more effective by heating the crank case oil to .a substantially higher temperature than the temperature at which it is Withdrawn from the motor crank case. Heating also prevents stoppage of screens and filters by the oil becoming cold and viscous. However, naval patrol vessels powered by internal combustion engines have no conveniently effective heating means available except electricity.

Therefore, the primary object of the present invention is to provide a compact and convenient heater for the heating of crank case lubricating oils in a purification cycle.

Aiurther object of the invention is to provide a compact and efiective electric heating apparatus for heating crank case this to be purified.

Another object of the invention is to provide improved method for refining crank case oils.

The improved electric heating apparatus of the present invention comprises an oil heating chamber divided into two heating sections in each of which is mounted a bank of electric heating units arranged so that the oil to be heated passes over the heating units in one compartment of the chamber and then over the heating units in the other compartment of the chamber. The apparatus includes other important features such as means for providing a pressure drop through the heating chamber as well as between the compartments in the chamber, a compact arrangement for the electric heating units and special The Oil is means for mounting the heating units in the ends of the heating chamber.

other objects, features and advantages of the process and apparatus of the present invention will be apparent to those skilled in the art from the following detailed description thereof taken in connection with the accompanying drawings in which:

Fig. l is a front view, partly in broken section, of an electric heating apparatus constructed in accordance with the invention.

Fig. 2 an end view of the heater shown in Fig. 1, with certain parts removed or broken away, taken on the line 2-2 of Fig. 1.

Fig. 3 is a broken longitudinal cross sectional View, taken on the line .3-3 of Fig. 2, of the heating chamber and other portions of the apparatus shown in Fig. 1 with the banks of heating units removed.

Fig. 4 is a longitudinal cross sectional view of one of the heating units employed in the heating apparatus of the present invention.

Fig. 5 is a view, partly in section, showing the arrangement of the heating units and the method of mounting the same.

Referring to Fig. '1 of the drawings, the electric heating apparatus of the present invention comprises in its preferred form a horizontal cylindrical oil heating chamber t0 provided with end flanges 12 to each of which is secured by bolts, as shown, a header H, the latter of which includes an integral header box [6 provided with a cover plate 18. The headers l4 in the illustrated embodiment of the present invention are used as mountings for banks of electric heating units 20, five of such units being shown as mounted in each header [4 and extending almost 'to the center of the cylindrical chamber l0. Each of the electric heating units 20 includes a shoulder 22 which bears against the inside of the header i4 and which is held there in fluid-tight manner by a ring nut 24 which is drawn up on the opposite side of the header on a threaded section of the heating unit which extends through the header into the header box I6. The ends of the heating units which extend into the chamber H], are supported, in spaced relation to each other by a metal spider 2B fastened to the end of each unit by means of screws, as shown. All metal parts or the apparatus are preferably made of brass.

Each of the electric heating units 20 includes a channeled outer shell or casing adapted to uniformly and rapidly heat the oil conducted through the Theater. The heater itself which is provided with mounting brackets 27 on each of the fianges I2, is installed in accordance with the preferred form of the invention, in a cycle provided for purifying the crank case oil from patrol vessel motors. The used crank case oil is withdrawn from the motor and conducted by means of a pump (not shown) to the heating chamber l through an inlet pipe 28. the oil being supplied through the line 28 at a moderate pressure of for example about lbs. per square inch. The oil supplied to the chamber l0 through' the line 28 passes through relatively small holes 32 in a metal angle distributor 34 mounted over the inlet 28, under the right heater bank and fastened to the partition 30 and to the shell of the chamber 10; to the latter by means of a bolt 36 (Fig. 3). The oil passes through the small holes :52 with a substantial pressure drop and is distributed over the heaters 20, over which it flows upwardly to the top of the chamber and then through a V- shaped opening in the partition 30 into the end of a second perforated metal angle distributor 38 exactly like the distributor 34 and mounted in substantially the same manner as shown in Fig. 1, except that it is above the bank of heating units to the left in the chamber Ill. The oil flows through the holes 32 in the distributor 38 with a further substantial pressure drop, and passes downwardly over the heating units to the left of the partition 30. The oil is finally discharged from the chamber l0 through a line 40.

One important function of the angle members 34 and 38 is to provide pressure reducing means to cause a pressure drop in the oil entering the first bank and between the banks of heaters. They also act to distribute the oil substantially uniformly over the heating units of each bank because the oil is forced through the small holes in the members 34 and 38 with a pressure drop. The oil taken from the motor or motors usually has a temperature of only about 140 F. and sometimes only about 130 F., andthe heating apparatus of the present invention is provided to bring the temperature up to about 200 F., at which temperature the oil is conducted through a centrifuge for the removal of sludge, small metal particles, and other impurities.- The oil discharged from the centrifuge is conducted through a filter and then to the motor oil storage tank for the motor or motors. From the storage tank the oil usually flows by gravity back to the motor or motors to keep them supplied with clean purified oil. The filter used may be a simple felt-type filter or one containing an adsorbent clay such as fullers earth or other refining clay.

Electricity for the heating units 20 is supplied to the heating apparatus through lead wires 42 which terminate in a water-tight conduit junction box 40. The lead wires 42 are attached respectively to metal connector plates 46 mounted on an insulation block or base 48 set in the box 44. The junction box 44 is mounted to the back and mostly above the heater shell l0 and connected up with fluid-tight connections to the header boxes l6 by means of two conduit nipples 50 which terminate respectively in suitably prepared lateral openings in integral projections 52 on the rim of each of the fianges Ill. The nipples 50 may be welded, brazed or otherwise secured in the positions shown in Figs. 1 and 3. Current is distributed from the plates 46 to connectors in the header boxe l6 through wires 54 and 56, respectively, which terminate in soldering lugs on the end of stud connectors 58, each of which are insulated from the metal. of the projection 52 by means of substantially cylindrical insulator bushings 60 and 62. The assembly of the lugged studs 58 and the bushings B0 and 02 is illustrated in Fig. 3, in which suitable nuts and washers are used. The insulator bushings 62 at each end of the heater, extend substantially beyond the face of the flange 12 and into a housing 64 which comprises an integral part of the header box 16 into which it opens as shown in Figs. 2 and 5. The cover plates [8 also have integral projections which cover the housings 64.

Electric current is distributed to the heating units 20 from connector studs 58 through distributor lead wires 66 in each of the header boxes l6. The five heaters 20, the heads of which extend into each header box 10, are supplied with current in parallel from the wires 66 by means of connector bars as shown which are attached to connector studs 68 extending from the head of each heating unit. The connector bars are fastened to the studs 68 by means of nuts, as shown. The heating units 20 are mounted in the headers I4 with the nuts 24 in such a manner that they are fluid-tight and the cover plate I8 is fluidtight with respect to the housing I6, so that it is impossible for any oil or water or other fluid to get into the housing 6. The bushing 60 and 62 also preferably form a fluid-tight joint between the respective conduit nipples 50 and the housings 64 and header boxes 16.

Each of the heating units 20 preferably comprises a solid metal casing H3, in this instance preferably brass (Fig. l). This metal case or shell is preferably made from a solid piece of stock by boring out the cavity for the electric resistance heating element and machining the outside by means of a suitable chasing tool to produce a number of narrow annular channels 12 separated by relatively thick walls or fins 14. By using a suitable tool, any number of the channels may be made in a single operation, and either before or after the boring step. The walls 14 which separate the narrow annular channels are preferably much thicker than that of the usual fins found in heat exchange apparatus. In a specific instance, the heater case for a 1000 watt heater was made from rolled brass stock of 1% inch diameter, the overall length of the case being 7 inches. It had the full diameter 'of 1% inches for the fins and a cavity V of an inch in diameter. The finned section included 50 fins occupying a distance of about 6% inches. The channels between the fins were about 0.062 inch wide, and rounded at the base, and about 0.10 inch wide at the periphery, so that the fins themselves were substantially thicker at'the base than at their periphery, for effective heat transfer. The fins were about 2; of an inch wide, and spaced at approximately 0.125 inch. The heating apparatus shown in the drawings, and containing ten of these 1000 watt heating units, was found to be suitable forheating about I50 gallons of lubrigating oil per hour from a temperature of about 130 F. to a temperature of 200 F.

The casing of the heating unit 20 includes an end section 16 which is threaded both internally and externally, the opposite end being cut and tapped for mounting on the spider 26. The electric resistance heating element in each of the units 20 includes a hollow cylindrical zircon core 18 and a resistance wire wrapped therearound in spaced convolutions throughout the length of the finned section of the heater. The terminals of the resistance wire extend from the end of the core and into a hard plastic insulation head :82 in which they are attached to the studs 68. "The resistance wire 80 may be ch'omium, nickelchromium alloy or aluminum-.cobalt-iron alloy.

In making up the heating unit 20, the resistance wire 80 and the core 18 are coated with a zircon wash made of 50% milled grain zircon and 50% of natural grain zircon bonded with a mixture of 6% P205 and 2% chromic acid. coating is hardened .onto the wire and the core by heating the element to a temperature of about 600F. in an oven. The core and resistance wire unit is mounted in the casing '10 by packing itiin the cavity therein in spaced relation from the shell, the space being filled with fine zirconsand 84 which is a good dielectric and has ahigh heat conductivity. The layer of sand 84 completely surrounds the core and resistance wire and may be' very densely packed by vibrating the casing as the sand is introduced around the core. The packed-in sand is held in place under the head 82 by means of a gasket member 86.

While the heating units '20 have been shown as cylindrical, they may have any other desired cross-section such as elliptical, tear-drop, triangular, rectangular, etc. In any of these shapes, however, the channels and dividing walls are preferably arranged so that relatively narrow deep channels are provided in planes at approximately right angles to the longitudinal axes of the units so that the oil passed 'thereover will be heated rapidly and uniformly. In the case of the heating units of circular cross-section as illustrated, the oil flows through channels on each side of each heater unit. In the arrangement as shown more particularly in Fig. 1, the banks of heaters are mounted so that the heating units extend substantially horizontally while the oil on both sides flows across the bank or in the same direction as the channels in the heater unit casing walls.

Regardless of the cross-sectional shape of the electric heating units mounted in eachEbank, they are preferably arranged so that the oil passed over each bank has little or no chance of avoiding the influence of the narrow channels or fins. Note for example that the five heating 'units mounted in the right compartment of the particular heater described, are arranged so that the two lower heating units 20 in conjunction with the middle unit 28, substantially screen the whole area over the distributor 34 (Fig.2), andthat the two upper heating units in conjunction with the middle unit substantially screen the distributor 38 in the left hand section of the heater. The size of the heating units 23, that is, the outside dimension of the fins, is such that three heaters substantially equal the internal diameter of the cylindrical chamber It]. Note that Fig. 5 shows the close mounting of the three heating units 20 which are in line with the housing 64. If desired, end plates substantially fitting the inside of the chamber l0 and the distributors 34 and 38, may replace the spiders 26. Other arrangements may be made with a larger number of heating units to accomplish substantially the same results, so that the oil introduced below or above the banks of heaters is substantially screened through the channels of the heating units. In fact, the arrangement, with the five heaters as illustrated, has two screens for each bank of heaters, one in the upper portion of the chamber and the other in the lower portion of the chamber ID. The fins of the outside heaters 20 may touch or almost touch the wall of the chamber l0 and the fins of heater casings (5, however, are pre the middle heating unit 2% with which they are aligned.

While the oil heating apparatus of the present invention has been illustrated as being mounted in a horizontal position, and this position has certain advantages as indicated above, the chamber 10 may nevertheless be mounted any other desired and necessary position since the angle of mounting has no appreciable influence on the operation of the heating apparatus, as long as .a pressure drop is provided at the inlet and between the compartments of chamber iii.

The heating apparatus of the present invention is easy .to keep clean and easy to keep in running order, since the bank of heating units on either side can be removed and cleaned as a bank or each individual heating unit 28 can be removed and cleaned separately or replaced if necessary. Furthermore, all :cf the electrical connections are readily accessible and easily replaced or repaired. The header boxes l5 always clean and iree from oil or water, and the houshig St is placed at the upper part of the heater .so that it is free from any contamination, even when one of the headers M is removed ironnthe heater.

The relatively thick closely spaced fi s or channel walls of the electric heating umts are oi considerable importance because the metal of which they are composed is integral par of the tubular shell of the heater itself and therefore conducts heat rapidly to relatively narrow bodies of oil in the channels. While it is preierre that the fins he of the shapes described and shown, somewhat similar results may be accomplished by cutting a continuous channel in the metal stock of the casing "it so as to leave a continuous thick tapered spiral tip. This arrangernent would of course have substantially the same type of channels as shown in the drawings. While in the present case the electric heating units as well as the whole eating appaI-atus is preferably made oi brass for its particular use in the process cycle described in connection with naval patrol vessels, the apparatus may be made of other metals. For example, whe.e its use required for air craft. the relatively light metals: aluminum, aluminum alloys, magnesium and magnesium alloys may be used. The electric i'a'oly made from metals of high heat conductivity such as brass, aluminum, copper or silver.

In describing the method of using the heater of the present invention in the refining oi used crankcase oils while in service, it was mentioned that a pump was to force the oil into heater through the line 28, However, a suitable pressure drop through the sections of the heater may be secured by attaching the pump to the outlet 46 and drawing the oil through the heater. Various other modifications may be made in the procedure and in the structure of the heating apparatus of the present invention without departing from the invention itself. Such modifications and changes are to be understood as coming within the scope of the invention as defined by the appended claims.

Having described the invention in its preferred form and illustrated the same in connection with certain specific examples, what is claimed as new is:

1. An electric oil heating apparatus, comprising a cylindrical chamber of substantially greater length than diameter having a header at each end and a partition wall dividing the chamber into two substantially equal compartments. a

bank of electric heating units mounted in each of said headers and extending into and substantially filling each compartment, a header box at each end of the chamber into which each of the electric heating units also extends, means for drop in the oil flowing from one compartment to the other and in the oil flowing into the inlet compartment of the chamber.

2. An electric oil heating apparatus, comprising a cylindrical chamber of substantially greater length than diameter having a header at each end and a partition Wall dividing the chamber into two substantially equal compartments, a bank of electric heating units mounted in each of said headers and extending into and substantially filling each compartment, a header box at each end of the chamber into which each of the electric heating units also extends, each of said units having a metal casing the outer surface of which is composed of deep narrow channels, means for supplying electric current to said header boxes and to the electric heating units extending thereinto, means for supplying oil to one of said compartments, for conducting the oil through an opening in the partition in said chamber into the other compartment and for discharging the heated oil from the last-mentioned compartment, and a pressure reducing distributor mounted in each compartment and adapted to cause a pressure drop in the oil flowing from one compartment to the other and in the oil flowing into the inlet compartment of the chamber.

3. An electric heating apparatus, comprising a tubular chamber of substantially greater length than width having a header at each end and a partition Wall dividing the chamber into two substantially equal compartments, a bank of relatively long narrow electric heating units mounted in each of said headers and extending into and substantially filling each compartment, a header box at each end of the chamber into which the connector head of each of the" electric heating units extends, means for supplying electric current to said header boxes and to the connector heads of the electric heating units extending thereinto, means for supplying a fluid to be heated to one of said compartments, for conducting it therefrom into the other compartment and for discharging the heated fluid from the lastmentioned compartment, and a distributor mounted in each compartment and adapted to cause substantially uniform distribution of the fluid over the bank of electric heating units therein.

4. An electric heating apparatus as defined by claim 3 in which said means for supplying electric current to said header boxes comprises a fluidtight junction box from which electric lead lines extend through conduit nipples to connectors mounted in said header boxes.

5. An electric oil heating apparatus, compris 6. An electric heating apparatus, comprising a tubular chamber of greater length than width,

having a bank of cylinder-shaped electric heating units extending into said chamber, each of said units including a metal shell having a thick cylindrical wall conttaining a large number of closely spaced deep annular channels separated by thick metal walls and which extend at substantially right angles to the longitudinal axis of the shell, means for supplying and discharging a fluid from said chamber arranged to cause the fluid to flow through said bank of heating units transversely to the axis of said shell and thereby flow through and be heated in said channels.

7. An electric oil heating apparatus comprising an oil heating chamber in which the oil is heated by a bank of relatively long narrow electric heating units mounted in the chamber and through which the oil to be heated is conducted, each of said units having a thick metal wall surrounding an electric resistance heating element,

said wall containing externally closely spaced. 

